Development of a Long-term Water Quality Monitoring Program for the Lower Snake River Reservoirs, Washington
by Gregory L. Geist
December 1996
M.S. Thesis. Environmental Science and Regional Planning.
Abstract
The Lower Snake River consists of a series of four reservoirs, each approximately 36 miles in length, that extend from Lewiston, Idaho at Snake River mile 139 to Pasco, Washington at the confluence of the Snake and Columbia Rivers. Dams impounding the Lower Snake River reservoirs were constructed by the U.S. Army Corps of Engineers (USACE) between 1955 and 1975. Operation and maintenance of the dams and reservoirs, including the funding and oversight of water quality investigations, is performed by the Walla Walla District USACE.
Limnological investigations performed by Falter and Funk (1973), Funk et al. (1985), and the recent (1994-1996) investigation conducted by the State of Washington Water Research Center have identified several areas of concern with regard to the general water quality of the Lower Snake River. Primary productivity levels are indicative of a eutrophic system, and blue-green algal blooms are commonly observed in the late-summer months. Additionally, high levels of phosphorus, nitrogen and suspended solids have occasionally been present in all of the Lower Snake River reservoirs.
The Walla Walla District USACE recently expressed interest in implementing a long-term monitoring program for the Lower Snake River reservoirs to assess trends in nutrients, trophic status and general water quality conditions. This document will provide the USACE with specific recommendations for the proper implementations of a monitoring program on the Lower Snake River. The objectives of this paper include: